Datasheet
TMC4361A Datasheet | Document Revision 1.22 • 2017-JAN-12
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Read entire documentation; especially the “Supplemental Directives” on page 224.
MAIN MANUAL
The LSB (last significant bit) of the whole cover datagram register is located at
COVER_LOW
(0). As long as
COVER_DATA_LENGTH
< 33, only
COVER_LOW
or parts
of this register are required for cover data transfer.
If more than 32 bits are necessary, the complete
COVER_LOW
and (parts of) the
COVER_HIGH
register are required for SPI cover data transfer.
NOTE:
Every SPI communication starts with the most significant bit (MSB).
OPTION 1: COVER_DATA_LENGTH < 33 BITS
In order to send a cover datagram - that is smaller than 33 bits - do as
follows:
Action:
Set
COVER_LOW
(
COVER_DATA_LENGTH
-1:0) register 0x6C = cover_data.
Result:
After a valid register request to
COVER_LOW
, SPI output is sent out
COVER_DATA_LENGTH
bits of
COVER_LOW
register.
OPTION 2: COVER_DATA_LENGTH > 32 BITS
In order to send a cover datagram - that consists of more than 32 bits - do
as follows:
Action:
Split cover data into two segments:
cover_data_low = cover_data(31:0).
cover_data_high = cover_data >> 32.
cover_data_high = cover_data(31:0).
Set
COVER_HIGH
(
COVER_DATA_LENGTH
−32:0) register 0x6D=cover_data_high
.
Set
COVER_LOW
register 0x6C = cover_data_low
.
Result:
After a valid register request to
COVER_LOW
, SPI output is sent out
COVER_DATA_LENGTH
bits that comprises register values of
COVER_HIGH
and
COVER_LOW
.
The cover register and the datagram structure are illustrated in the figure below:
Figure 54: Cover Data Register Composition (CDL – COVER_DATA_LENGTH)
Continued on next page.
bit
63
bit
62
bit
33
bit
32
...
bit
31
bit
30
bit
1
bit
0
...
bit
31
bit
30
bit
1
bit
0
...
COVER_HIGH
COVER_LOW
Cover register bit
31
bit
30
bit
1
bit
0
...
MSB if CDL=63
MSB if CDL=30
(COVER_HIGH not
required)
Sending Cover
Datagrams
Cover
Datagrams with
32 Bits